Seventy-seven patients who had sustained multisystem trauma, including severe blunt chest injury, were prospectively evaluated to assess the frequency of associated traumatic myocardial injury. Traumatic injury to either the right or left ventricle was defined by the presence of discrete abnormalities of wall motion on electrocardiographically gated cardiac scintigraphy in patients without a clinical history of heart disease. Forty-two patients (55%) (Group 1) had focal abnormalities of wall motion; 27 involved the right ventricle, 7 the left ventricle, 7 were biventricular, and 1 involved only the septum. Both the right and left ventricular ejection fractions were significantly (p less than 0.01) lower (31 +/- 11% and 47 +/- 14%, respectively) than those in the 35 traumatized patients without wall motion abnormalities on scintigraphy (Group 2) (49 +/- 8% and 58 +/- 11%, respectively). Repeat scintigraphic examination in 32 Group 1 patients at a time remote from initial injury showed improvement or resolution of previously defined focal wall motion abnormalities in 27 of 32 patients (84%). The electrocardiogram and serum enzyme tests were insensitive indexes of traumatic myocardial injury when defined by the scintigraphic abnormalities. Thus, severe blunt chest trauma results in a higher frequency of traumatic myocardial injury than heretofore recognized, and frequently involves the anteriorly situated right ventricle.